The circumstances of his drowning on Canoe Lake in Algonquin Park, linked with his image as a master canoeist, led to unsubstantiated but persistent rumours that he had been murdered or committed suicide.

[18] A year later, he entered a machine shop apprenticeship at an iron foundry owned by William Kennedy, a close friend of his father, but left only eight months later.

[37] Albert Robson, then the art director at Grip, recalled that Thomson's early work at the firm was mostly in lettering and decorative designs for booklets and labels.

[3] MacDonald left Grip in November 1911 to do freelance work and spend more time painting,[48] after the Ontario government purchased his canvas By the River (Early Spring) (1911).

Covering eighteen rectangular townships in Central Ontario, the Park was created to provide a space dedicated to recreation, wildlife and watershed protection, though logging operations continued to be permitted.

[59][60] Much of his artwork from this trip, mainly oil sketches and photographs, was lost during two canoe spills;[59] the first was on Green Lake in a rain squall and the second in a series of rapids.

[71] Addison and Little suggest that he guided fishing tours,[72][73] although Hill finds this unlikely since Thomson had only spent a few weeks in the Park the previous year.

[45] Harris expressed similar sentiments, writing that Thomson "had no opinion of his own work", and would even throw burnt matches at his paintings.

Jackson described the Studio Building as "a lively centre for new ideas, experiments, discussions, plans for the future and visions of an art inspired by the Canadian countryside".

[103] Mark Robinson and Thomson's family said that he was turned down after multiple attempts to enlist, likely due to his poor health and age but also possibly because he had flat feet.

Margaret Fairbairn of the Toronto Daily Star wrote, "Mr. Tom Thomson's 'The Birches' and 'The Hardwoods' show a fondness for intense yellows and orange and strong blue, altogether a fearless use of violent colour which can scarcely be called pleasing, and yet which seems an exaggeration of a truthful feeling that time will temper.

"[127] A more favourable take came from artist Wyly Grier in The Christian Science Monitor: Tom Thomson again reveals his capacity to be modern and remain individual.

[148][152][note 12] Under the direction of Thomson's older brother George, the body was exhumed two days later, and re-interred on July 21 in the family plot beside the Leith Presbyterian Church in what is now the Municipality of Meaford, Ontario.

[153][154][155] In September 1917, J. E. H. MacDonald and John William Beatty erected a memorial cairn at Hayhurst Point on Canoe Lake, to honour Thomson where he died.

Hunter expands on this thought, writing, "I am convinced that people's desire to believe the Thomson murder mystery/soap opera is rooted in the firmly fixed idea that he was an expert woodsman, intimate with nature.

[59][60] His first trips to Algonquin Park inspired him to follow the lead of fellow artists in producing oil sketches of natural scenes on small, rectangular panels for easy portability while travelling.

These artists shared an appreciation for rugged, unkempt natural scenery, and all used broad brush strokes and a liberal application of paint to capture the beauty and colour of the Ontario landscape.

[165][166] The larger canvases were instead completed over the winter in Thomson's studio—an old utility shack with a wood-burning stove on the grounds of the Studio Building, an artist's enclave in Rosedale, Toronto.

[171][172] Although few of the larger paintings were sold during his lifetime, they formed the basis of posthumous exhibitions, including one at Wembley in London in 1924, that eventually brought his work to international attention.

David Silcox has described these paintings as "the visual equivalent of a national anthem, for they have come to represent the spirit of the whole country, notwithstanding the fact that vast tracts of Canada have no pine trees",[179] and as "so majestic and memorable that nearly everyone knows them".

He normally depicted trees as amalgamated masses, giving "form structure and colour by dragging paint in bold strokes over an underlying tone".

[188] Byng Inlet, Georgian Bay shows the broken, high-keyed colour that Thomson and his colleagues experimented with later in his career, and is similar to Lismer's Sunglow.

[204] Thomson's time spent as a child collecting samples with his naturalist relative William Brodie may have similarly influenced him, though his interest in painting flowers seems to have been more focused on patterning and decoration than on the horticultural specifics of the subject.

[211] In all the sketches, he redirected emphasis from the delicacy of the flowers towards simple broad strokes of colour, something Harold Town thought "[imparted] a toughness of design sometimes missing in his harder themes of rock and bracken".

[49] As well, the white birches present in many paintings only thrive in "sunny, open areas whose previous tree cover had been removed",[220] meaning that logging was in some way necessary for them to flourish.

"[224] Paul Walton of McMaster University noted that Thomson occasionally referenced both the lumbering and tourism practices of Algonquin Park and "did not entirely ignore the damaging effects of logging on the environment ... but for the most part he concentrated on newly opened vista of sky and water or on finding decorative patterns of colour, form, and texture in the tangle of underbrush, smaller trees, and bared rock, the 'bush' that was often the remnant of the original forest.

"[225] Jackson first noted these distinctions in Thomson's works, from those "showing a low shore line and a big sky" and those "finding happy color motives amid [the] tangle and confusion" of "his waste of rock and swamp.

He described Figure of a Lady, Laura differently, interpreting it as a tender work, "well-designed and plainly expressed, this loving picture is so secure in intention that it survives, indeed triumphs, over the severe cracking of the paint".

"[233] Murray notes that Thomson's influence can be seen in the work of later Canadian artists, including Rae Johnson, Joyce Wieland, Gordon Rayner and Michael Snow.

[238] One example of the demand his work has achieved is the previously lost Sketch for Lake in Algonquin Park; discovered in an Edmonton basement in 2018, it sold for nearly half a million dollars at a Toronto auction.